A Summary of Progress in Petrography. in 1887-1896 |
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Page 9
... schists from the neighborhood of Ax embrace zircon , apatite , sphene , magnetite , and numerous other materials , thought to be due to the action of the granulite on the schists . On the granulite side of the contact this rock is found ...
... schists from the neighborhood of Ax embrace zircon , apatite , sphene , magnetite , and numerous other materials , thought to be due to the action of the granulite on the schists . On the granulite side of the contact this rock is found ...
Page 14
... schists . The chondri , on the other hand , are thought to be of cosmic origin , since they are similar to the chondri obtained in deep - sea soundings . If the amount of the dust collected from the snow in Greenland represents the fall ...
... schists . The chondri , on the other hand , are thought to be of cosmic origin , since they are similar to the chondri obtained in deep - sea soundings . If the amount of the dust collected from the snow in Greenland represents the fall ...
Page 14
... schists have been looked upon as dynamo - metamorphosed phases of the protogine . Both of these views the author combats . Among the schists he finds eclogites , with diop- side in micropegmatitic intergrowths with quartz and ...
... schists have been looked upon as dynamo - metamorphosed phases of the protogine . Both of these views the author combats . Among the schists he finds eclogites , with diop- side in micropegmatitic intergrowths with quartz and ...
Page 14
... schists are mentioned graphitic sericite- schists , with well - developed crystals of tourmaline and hematite , and a chloritic amphibolite whose principal feldspar is albite . Gabbros and peridotites cut the Paleozoic strata . In ...
... schists are mentioned graphitic sericite- schists , with well - developed crystals of tourmaline and hematite , and a chloritic amphibolite whose principal feldspar is albite . Gabbros and peridotites cut the Paleozoic strata . In ...
Page 22
... schists , in which contact alteration has been effected . The tonalite is the rock so well known as comprising a ... schists : a younger series including phyllites and epidote - amphibolites , and an older one embracing gneiss and ...
... schists , in which contact alteration has been effected . The tonalite is the rock so well known as comprising a ... schists : a younger series including phyllites and epidote - amphibolites , and an older one embracing gneiss and ...
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Common terms and phrases
acid Al,O alteration Amer AMERICAN NATURALIST analysis andalusite angle aragonite augite axial ratio basalts beryl biotite brucite Bull calcite calcium chlorite cleavage Colby University color colorless composition constituents containing cordierite corresponding crystalline crystals density described diabase double refraction dyke eruptive rocks Fe,O Fe₂O feldspar FeO MgO CaO FeO MnO forms formula Franc gabbro-diorites gabbros garnet Genth gneisses granite granulites ground-mass H₂O habit hexagonal hornblende humite hypersthene imbedded inclusions Jour Kryst leucite masses melanophlogite metacinnabarite mica mineral MINERALOGY AND PETROGRAPHY.¹ Mitth molecules muscovite Neues Jahrb nosean occur olivine optical original orthoclase ottrelite parallel Penfield Petrog PETROGRAPHY.¹ Petrographical phenacite plagioclase plane plates polymorphism prismatic produced pseudomorphs pyroxene quartz regarded rock individual Rosenbusch schistose schists serpentine silica sodium soluble specific gravity specimens spinel structure substance sulphur symmetry tabular temperature tonalite tourmaline twinned varieties W. S. Bayley Waterville yielded Zeits zircon zone
Popular passages
Page 19 - The plane of the optical axes is perpendicular to the plane of symmetry, and makes with c an angle of °7 in acute /9. A = b. 2H na = 104° 27'.
Page 14 - The larger part of the dust is thought to be a sediment from the air, and to have been obtained by it from a region of crystalline schists. The chondri, on the other hand, are thought to be of cosmic origin, since they are similar to the chondri obtained in deep-sea soundings. If the amount of the dust collected from the snow in Greenland represents the fall of one year, the total amount falling upon the entire surface of the earth in this time is 125 million kilograms, equivalent to a cube of thirty-one...
Page 14 - Wiilfing 21 for investigation, by whom it has been found to consist in greater part of feldspar, quartz, mica, and hornblende. There are present in it also garnet, zircon, magnetite, augite, and sillimanite, and with them is mixed a nitrogenous organic substance. The most interesting constituents of the dust...